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| Titel |
Dynamical model for the evolution of Dst |
| VerfasserIn |
Richard Boynton, Michael Balikhin, Stephen Billings, Ping li |
| Konferenz |
EGU General Assembly 2011
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 13 (2011) |
| Datensatznummer |
250055205
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| Zusammenfassung |
| A mathematical model for the dynamics of the Dst index has been identified using the
NARMAX OLS-ERR methodology. The NARMAX OLS-ERR algorithm, which is widely
used in the field of system identification, is able to identify a mathematical model of a wide
class of nonlinear systems using input and output data sets. The Dst index is used as the
output and a solar wind-magnetosphere coupling function is used as one of the inputs, along
with a pressure term and an IMF term. The correlation function is often used to justify
coupling functions, however, the correlation function does not work for nonlinear systems.
Recently, as an alternative, the error reduction ratio (ERR) which is part of the NARMAX
model structure selection, has been used to assess prediction capability of various coupling
functions. In this study, it was shown that p1-2V 4-3BT sin6(θ-2) was statistically the most
appropriate coupling function. The study deduced analytically that the factor sin6(θ-2)
must appear in previous theoretical models (Kan and Lee). It is this newly deduce
coupling function that has been used as an input to model the Dst dynamics. It
was shown that forecasting ability of the identified model are superior to previous
models. |
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